Techno Press
Techno Press

Structural Engineering and Mechanics   Volume 60, Number 3, November10 2016, pages 387-404
DOI: http://dx.doi.org/10.12989/sem.2016.60.3.387
 
Failure life estimation of sharp-notched circular tubes with different notch depths under cyclic bending
Kuo-Long Lee, Kao-Hua Chang and Wen-Fung Pan

 
Abstract     [Full Text]
    In this paper, the response and failure of sharp-notched 6061-T6 aluminum alloy circular tubes with five different notch depths of 0.4, 0.8, 1.2, 1.6 and 2.0 mm subjected to cyclic bending were experimentally and theoretically investigated. The experimental moment-curvature relationship exhibits an almost steady loop from the beginning of the first cycle. And, the notch depth has almost no influence on its relationship. However, the ovalization-curvature relationship exhibits a symmetrical, increasing, and ratcheting behavior as the number of cycles increases. In addition, a higher notch depth of a tube leads to a more severe unsymmetrical trend of the ovalization-curvature relationship. Focusing on the aforementioned relationships, the finite element software ANSYS was used to continue the related theoretical simulation. Furthermore, the five groups of tubes tested have different notch depths, from which five unparallel straight lines can be observed from the relationship between the controlled curvature and the number of cycles required to produce failure in the log-log scale. Finally, a failure model was proposed to simulate the aforementioned relationship. Through comparison with the experimental data, the proposed model can properly simulate the experimental data.
 
Key Words
    failure life estimation; sharp-notched circular tubes; cyclic bending; moment; curvature; ovalization; finite element ANSYS analysis
 
Address
Kuo-Long Lee: Department of Innovative Design and Entrepreneurship Management, Far East University, No. 49, Chung Hua Rd., Hsin-Shih Dist., Tainan 744,Taiwan
Kao-Hua Chang: Department of Mold and Die Engineering, National Kaohsiung University of Applied Sciences, No. 415, Chien Kung Rd., Kaohsiung 807,Taiwan
Wen-Fung Pan: Department of Engineering Science, National Cheng Kung University, No. 1, University Rd., Tainan 701, Taiwan
 

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